Impact of Formulary Restrictions on Antiepileptic Drug Dispensation Outcomes.

INTRODUCTION

The aim of this analysis was to assess the relationship between formulary restrictions and antiepileptic drug (AED) dispensation in patients with focal seizure (FS).

STUDY DESIGN

A retrospective cohort analysis was conducted using data from Symphony Health's Integrated Dataverse® (1 April 2015-30 June 2018).

METHODS

This study included two patient populations: the overall patient population (N = 54,097) and a pediatric population (< 18 years) (N = 12,610). Cohorts were defined based on approval or rejection of the index AED claim. Study outcomes were prescription life cycle analysis, proportion of patients with dispensation, time to dispensation, and likelihood of successful dispensation. A multivariable Cox proportional hazards model was estimated to study the association between formulary restriction and likelihood of successful AED dispensation.

RESULTS

Among patients in the overall population with a rejected claim (n = 9133), 8.0% did not receive any AED and 77.6% received approval for the index AED following an appeal. Among the pediatric patients with a rejected claim (n = 3081), 6.0% did not receive any AED and 81.7% received approval for the index AED after an appeal. In both populations, formulary restrictions were associated with significant delays in index AED dispensation (6.9 and 5.3 days, respectively; P  < 0.0001 for each population), compared to approved AED claims. In the overall and pediatric populations, formulary-related rejections of AEDs were associated with a 35% (hazard ratio [HR] 0.65; 95% confidence interval [CI] 0.64-0.66; P  < 0.0001) and 27% (HR 0.73; 95% CI 0.69-0.76; P  < 0.0001) lower likelihood of successful dispensation of the index AED, respectively.

CONCLUSIONS

Formulary restrictions of AEDs were associated with significant delays in treatment and significantly lower likelihood of successful AED dispensation in patients with FS.